444 research outputs found
High Rate Detection of Volatile Products Using Differential Electrochemical Mass Spectrometry: Combining an Electrode-Coated Membrane with Hydrodynamic Flow in a Wall-Tube Configuration
We present an experimental system that combines differential electrochemical mass spectrometry with hydrodynamic flow consisting of an impinging jet in a wall-tube configuration. This assembly allows simultaneous detection of electrochemical signals along with monitoring of dissolved gas species using differential electrochemical mass spectrometry under well-defined hydrodynamic conditions and over a wide range of mass transfer rates. The working electrode is deposited directly onto a thin, hydrophobic membrane, which also serves as the inlet to the mass spectrometer. This inlet provides extremely rapid mass detection as well as a high flux of products from the electrode surface into the mass spectrometer. The impinging jet is designed in a wall-tube configuration, in which the jet diameter is large compared to the electrode diameter, thus providing uniform and rapid mass transfer conditions over the entirety of the electrode surface. This combination of rapid detection and controllable flow conditions allows a wide range of hydrodynamic conditions to be accessed with simultaneous electrochemical and mass spectrometric detection of dissolved gas species, which is important in the analysis of a range of electrochemical reactions. The capabilities of this configuration are illustrated using a platinum-coated electrode and several electrochemical reactions, including ferrocyanide oxidation, proton reduction, and oxalic acid oxidation
La vita in una goccia d'acqua: spunti per un'azione didattico-educativa.
Il progetto \ue8 stato presentato dal Consiglio Direttivo della SIP (Societ\ue0 Itlaiana di Protistologia ONLUS). L\u2019obiettivo principale di questo progetto \ue8 quello di costituire ed organizzare un\u2019iniziativa didatticoformativapresso gli insegnanti di scienze della scuola secondaria di primo grado, come educatori
della classe dei giovani in et\ue0 scolare, volta a sviluppare le cognizioni scientifico-applicative
sull\u2019importanza dei microorganismi unicellulari eucariotici, comunemente definiti "protisti", in
ambito sanitario e ambientale.
Molto spesso dei protisti, i principali artefici del pi\uf9 grande salto evolutivo nella storia dei viventi,
non esiste il bench\ue9 minimo accenno. La principale ragione di tale incompletezza sta nella non
facile presentazione di tali organismi. I protisti, infatti, hanno dimensioni microscopiche e quindi
non sono visibili ad occhio nudo. Eppure, questi organismi, oltre ad avere un elevata importanza
evolutiva, sono indicatori di qualit\ue0 dell\u2019ambiente oltre ad essere di imponente interesse sanitario. I
protisti di tipo parassitologico sono gli agenti infettanti di malattie molto gravi, quali la malaria, la
toxoplasmosi e la leishmaniosi, tra le pi\uf9 note, e rivestono, oggi, grande importanza nei progetti
d\u2019interesse prioritario per gli interventi istituzionali di sanit\ue0 pubblica in Italia e nel resto del
mondo, ma di essi e delle loro infezioni ben poco sanno gli operatori e gli utenti della scuola
secondaria dove, invece, il messaggio educazionale pu\uf2 essere molto efficiente anche in termini di
prevenzione. Per tutto questo \ue8 molto importante promuovere la conoscenza di tale \u201cmondo
sommerso\u201d nel quale esistono organismi sia da evitare in quanto patogeni (prevenzione primaria)
che da promuovere in ambienti naturali (monitoraggio ambientale e controllo dell\u2019inquinamento).
Il secondo obiettivo \ue8 quello di mettere al servizio di questa iniziativa le conoscenze scientifiche
che vengono dalla ricerca, la pi\uf9 specializzata, come quella perseguita dai ricercatori che nel
progetto svolgono le docenze.
Contestualmente, il terzo obiettivo \ue8 quello di sopperire alla mancanza di informazioni sui protisti,
rendendo evidente, attraverso l\u2019allestimento di una sala didattico-espositiva presso il Museo del
Mare che ha sede nell\u2019Area Marina Protetta (AMP) Torre del Cerrano, l\u2019immagine di questo
microcosmo, che svela i principali fenomeni che regolano la vita sulla Terra e che svolge un
importante ruolo per la conservazione della biodiversit\ue0 sul nostro pianeta. Quest\u2019ultimo obiettivo \ue8
raggiunto anche dagli insegnanti e dai loro studenti, mettendo in uso le conoscenze ottenute nel
corso del progetto, tramite l\u2019utilizzo della sala didattico-espositiva come un laboratorio di ricerca.
In base a quanto sopra esposto possiamo dire che i risultati attesi da questo progetto sono:
1. Accrescimento delle cognizioni tecnico-scientifiche da parte degli insegnanti di scienze della
scuola secondaria arruolati nel progetto nel settore della Protistologia, con particolare riguardo
all\u2019importanza evolutiva e applicativa nel settore ambientale e sanitario dei protisti.
2. Ricaduta di queste cognizioni sugli studenti delle classi coinvolte, come risultato
dell\u2019adempimento didattico dei suddetti insegnanti e rafforzamento delle stesse tramite
l\u2019utilizzazione della sala didattico-espositiva come laboratorio applicativo di lavori di gruppo sul
tema dei protisti e del loro coinvolgimento nella qualit\ue0 dell\u2019ambiente e della salute.
3. Ottenimento della collaborazione tra ricerca universitaria, scuola e aree marine protette in
maniera sinergica
Polyvinylpyridine-supported palladium nanoparticles: An efficient catalyst for Suzuki–Miyaura coupling reactions
Palladium nanoparticles (Pd NPs) synthesized by the metal vapor synthesis technique were supported on poly(4-vinylpyridine) 2% cross-linked with divinylbenzene (Pd/PVPy). Transmission electron microscopy revealed the presence of small metal nanoparticles (dm = 2.9 nm) highly dispersed on the PVPy. The Pd/PVPy system showed high catalytic efficiency in Suzuki-Miyaura carbon–carbon coupling reactions of both non-activated and deactivated aromatic iodides and bromides with aryl boronic acids, carried out under an air atmosphere. The high turnover of the catalyst and the ability of the PVPy resin to retain active Pd species are highlighted. By comparing the catalytic performances of Pd/PVPy with those observed by using commercially available Pd-based supported catalysts, the reported system showed higher selectivity and lower Pd leaching
Macro-habitat preferences by the African manatee and crocodiles – ecological and conservation implications
African manatees (<i>Trichechus senegalensis</i>) and crocodiles are threatened species in parts of their range. In West Africa, crocodiles may constitute the main predators for manatees apart from humans. Here, we explore the macro-habitat selection of manatees and two species of crocodiles (West African crocodiles <i>Crocodylus suchus</i> and dwarf crocodile <i>Osteolaemus tetraspis</i>) in the Niger Delta (Nigeria), testing the hypotheses that (i) manatees may avoid crocodiles in order to minimize risks of predation, and (ii) the two crocodile species do compete. The study was carried out between 1994 and 2010 with a suite of different field techniques. We observed that the main macro-habitat types were freshwater rivers and coastal lagoons for manatees, mangroves for West African crocodiles, and rivers and creeks for dwarf crocodiles, with (i) the three species differing significantly in terms of their macro-habitat type selection, and (ii) significant seasonal influence on habitat selection of each species. Null models for niche overlap showed a significantly lower overlap in macro-habitat type use between manatee and crocodiles, whereas the two crocodiles were relatively similar. Null model analyses did not indicate any competitive interactions between crocodiles. On the other hand, manatees avoided macro-habitats where crocodiles, and especially West African crocodiles, are abundant
Macro-habitat preferences by the African manatee and crocodiles – ecological and conservation implications
Abstract. African manatees (Trichechus senegalensis) and crocodiles are threatened species in parts of their range. In West Africa, crocodiles may constitute the main predators for manatees apart from humans. Here, we explore the macro-habitat selection of manatees and two species of crocodiles (West African crocodiles Crocodylus suchus and dwarf crocodile Osteolaemus tetraspis) in the Niger Delta (Nigeria), testing the hypotheses that (i) manatees may avoid crocodiles in order to minimize risks of predation, and (ii) the two crocodile species do compete. The study was carried out between 1994 and 2010 with a suite of different field techniques. We observed that the main macro-habitat types were freshwater rivers and coastal lagoons for manatees, mangroves for West African crocodiles, and rivers and creeks for dwarf crocodiles, with (i) the three species differing significantly in terms of their macro-habitat type selection, and (ii) significant seasonal influence on habitat selection of each species. Null models for niche overlap showed a significantly lower overlap in macro-habitat type use between manatee and crocodiles, whereas the two crocodiles were relatively similar. Null model analyses did not indicate any competitive interactions between crocodiles. On the other hand, manatees avoided macro-habitats where crocodiles, and especially West African crocodiles, are abundant
Total Synthesis of Asparenydiol by Two Sonogashira Cross-Coupling Reactions Promoted by Supported Pd and Cu Catalysts
Asparenydiol, which is an important natural compound with potential pharmacological activities, was synthesized through two Sonogashira cross-coupling reactions catalyzed by supported Pd and Cu catalysts and by a Mitsunobu etherification. The optimization of the Sonogashira couplings allowed the use of catalysts supported on different matrices with good results in terms of catalytic efficiency and yields
Genetic diversity in section Rhizomatosae of the genus Arachis (Fabaceae) based on microsatellite markers.
Developing a questionnaire evaluating knowledge, attitudes and behaviors on audit & feedback among general practitioners. A mixed methods study
Background: Audit and Feedback (A&F) is one of the most common strategies used to improve quality in healthcare. However, there is still lack of awareness regarding the enabling factors and barriers that could influence its effectiveness. The aim of this study was to develop a questionnaire to measure the knowledge, attitudes and behaviors of general practitioners (GPs) regarding A&F. The study was performed in the context of the EASY-NET program (project code NET-2016-02364191). Methods: The survey was developed according to two steps. Firstly, a scoping review was performed in order to map the literature on the existing similar instruments with the aim of identifying the sub-domains and possible items to include in a preliminary version of the questionnaire. In the second phase, the questionnaire was reviewed by a multidisciplinary group of experts and administrated to a convenience sample in a pilot survey. Results: Ten papers were included in the scoping review. The survey target and development methodology were heterogenous among the studies. The knowledge, attitudes and behaviors domains were assessed in six, nine and seven studies, respectively. In the first step, 126 pertinent items were extracted and categorized as follows: 8 investigated knowledge, 93 investigated attitudes, and 25 investigated behaviors. Then, 2 sub-domains were identified for knowledge, 14 for attitudes and 7 for behavior. Based on these results, a first version of the survey was developed via consensus among two authors and then revised by the multidisciplinary group of experts in the field of A&F. The final version of the survey included 36 items: 8 in the knowledge domain, 19 in the attitudes domain and 9 in the behaviors domain. The results of the pilot study among 15 GPs suggested a good acceptability and item relevance and accuracy, with positive answers totaling 100% and 93.3% in the proposed questions. Conclusions: The methodology used has shown to be a good strategy for the development of the survey. The survey will be administrated before and after the implementation of an A&F intervention to assess both baseline characteristics and changes after the intervention
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